Here, we present a protocol for ultra-low detection of hydrogen peroxide based on the synergistic Nernst effect. This protocol covers the fabrication of stacked-layer poly(3,4-ethylenedioxythiophene): bromothymol blue (PEDOT: BTB)/polystyrene sulfonate (PEDOT: PSS), and platinum microelectrode (Pt), as well as the determination of the optimal operating point for the as-constructed H2O2 sensor.
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Method Article
Ultra-Low Hydrogen Peroxide Detection via Synergistic Nernst Potential Effect in Organic Electrochemical Transistors
In This Article
Summary
Abstract
The organic electrochemical transistor (OECT)-based synergistic Nernst potential—generated via the Pt gate electrode catalyzing hydrogen peroxide (H2O2) and the interaction between bromothymol blue (BTB) molecules and hydrogen ions (the by-product of H2O2 catalysis)—is leveraged for the ultra-low detection of H2O2 down to 1.8 × 10-12 M, with a broad linear detection range from 10-11 M to 10-3 M. The formation of this potential is determined by selecting a source-drain voltage (VDS) and a gate voltage (VG) of −0.6 V as the optimal operating points, and by adopting the stacked-layer poly(3,4-ethylenedioxythiophene):bromothymol blue/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:BTB/PEDOT:PSS) as the semiconducting channel material. In addition, relevant verification is provided by characterizing the carrier (de)doping capability of the stacked layers using UV–vis spectroscopy, identifying the optimal operating point via electrochemical measurements, and evaluating the sensing performance of the as-constructed OECT-based H2O2 sensor using single-stage constant-voltage scanning. Finally, the OECT-based H2O2 sensor is fabricated via a micro-nano manufacturing process, including the preparation of stacked semiconducting layers by spin-coating and the fabrication of microelectrodes via the lift-off process and magnetron sputtering. This methodology can open a broad avenue for the ultra-low detection of analytes through enzyme-catalyzed reactions.
Introduction
Hydrogen peroxide (H2O2) is a ubiquitous by-product of numerous enzyme-catalyzed biochemical reactions, including those mediated by lactate oxidase, glutamate oxidase, and glucose oxidase1. Its pervasive presence in a wide range of physiological and pathological processes2,3,4 makes it a critical biomolecule for understanding human health and disease states. Therefore, accurate detection of H2O2 at ultra-low concentrations is essential for gaining precise insights into bodily conditions, driving significant i....
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Protocol
1. Fabrication and characterization of stacked PEDOT: BTB/PEDOT: PSS semiconductor film
- Sample preparation
NOTE: When preparing the single-layer PEDOT: PSS, do Step 1.1.1. When preparing the stacked-layer PEDOT: BTB/PEDOT: PSS, perform Step 1.1.2.- Prepare the single-layer PEDOT: PSS via spin-coating.
- Filter the commercial PEDOT: PSS solution using a 0.45 μm filter (polyethersulfone PES).
- Take 884 μL of filtered PEDOT: PSS, 1 μL of 0.1 wt% dodecylbenzene sulfonic acid (DBSA), 50 μL of 5 wt% ethylene glycol (EG), and 5 μL of 0.5 wt% 3-glycidoxypropyltrimethoxysilane (GOPS)....
- Prepare the single-layer PEDOT: PSS via spin-coating.
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Results
This paper initially characterizes the stacked-layer PEDOT: BTB/PEDOT: PSS channel material using SEM, AFM, UV-vis spectroscopy, and electrochemical measurement. SEM and AFM images (Figure 1 and Figure 2) reveal that the 241 nm-thick stacked-layer PEDOT: BTB/PEDOT: PSS exhibits abundant granular structures, in contrast to the relatively smooth surface of the 120 nm-thick single-layer PEDOT: PSS film. The root-mean-square roughness (Rq) values ar.......
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Discussion
The success of the protocol relies on three interdependent critical steps, each validated by experimental characterization. Firstly, the fabrication of the stacked-layer channel material (Protocol 1.1) requires precise control over PEDOT: PSS spin-coating (4200 rpm for 60 s, followed by baking at 130 °C) and PEDOT: BTB electrodeposition (where the short-circuited PEDOT: PSS channel serves as the working electrode, with an electric potential ranging from 0 to 1 V at a scan rate of 0.1 V s⁻.......
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Disclosures
The authors have no conflicts of interest to disclose.
Acknowledgements
This research was supported by the National Natural Science Foundation of China (52175542 and 52203316), Science and Technology Cooperation and Exchange Special Project of Shanxi Province (No. 202304041101032), Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province (20240007), Research Project Supported by Shanxi Scholarship Council of China (No. 2024062), Patent Transformation Special Program of Shanxi Province (No. 202304012), China Postdoctoral Science Foundation (No. 2024M762331) Natural Science Foundation of Shanxi Province (No. 20210302123136 and 202103021223068), and the Shanxi Province doctoral innovation stat....
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Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| 10× Phosphate Buffered Saline (PBS) | Lanbolide Trading Co., LTD | P7209 | Purity: ≥99% |
| 3,4-ethylenedioxythiophene (EDOT) | Shanghai Aladdin Biochemical Technology Co., Ltd., China | E105649-25g | Purity: ≥99% |
| 3-glycidoxypropyltrimethoxysilane (GOPS) | Shanghai Aladdin Biochemical Technology Co., Ltd., China | G107576 | Purity: ≥97% |
| Developer | Suzhou Yancai Weina Technology Co., Ltd. | AZ 400K | |
| Bromothymol Blue (BTB) | Sinopharm Group Chemical Reagent Co., LTD | B801811-25g | Purity: ≥95% |
| Deionized water | Shanghai Aladdin Biochemical Technology Co., Ltd., China | W119424 | 18.2 M cm |
| Digital microscope | Olympus Corporation of Japan | DSX1000 | A cursory observation of the as-prepared OECT's channel |
| Dodecyl benzene sulfonic acid (DBSA) | Shanghai Aladdin Biochemical Technology Co., Ltd., China | D106550 | Purity: ≥90% |
| Dual potentiostatic electrochemical workstation | Metrohm AG, Switzerland | VIONIC | |
| Dual-port SourceMeter | Tek Technology Co., LTD | Keithley 2636B | |
| Dual-target magnetron sputtering | Shenyang Kejing Automation Equipment Co., LTD | VTC-600-2HD | |
| Ethylene glycol (EG) | Shanghai Aladdin Biochemical Technology Co., Ltd., China | E119700 | Purity: ≥99.8% |
| Hydrogen peroxide (H2O2) | Huize Biochemical Company | EL | Purity: ≥35% |
| N-methyl1-2-pyrrolidone (NMP) | Sigma-Aldrich (Shanghai) Trading Co., Ltd. | 328634 | Purity: ≥99.5% |
| Poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT: PSS) | Sigma-Aldrich (Shanghai) Trading Co., Ltd. | 739332 | Purity: ≥99.7% |
| Polyethylene terephthalate (PET) | Sigma-Aldrich (Shanghai) Trading Co., Ltd. | GF09063581 | |
| Potassium nitrate (KNO3) | Sinopharm Group Chemical Reagent Co., LTD | 10017218 | Purity: ≥99.0% |
| Photoresist | Suzhou Yancai Micro-Nano Technology Co., LTD | ROL-7133 | |
| Scanning Electron Microscope (SEM) | Carl Zeiss Company of Germany | Gemini Sigma 300 | |
| Spin coater | Jiangsu Leibo Scientific Instrument Co., LTD | EZ4 | |
| Sulfuric acid (H2SO4) | Sinopharm Group Chemical Reagent Co., LTD | 10021608 | 95.0-98.0% |
| Atomic Force Microscopy (AFM) | Bruker Corporation of the United States | Bruker Dimension Icon | |
| Ultraviolet laser marking machine | Shanghai Cifang Electrical Technology Co., LTD | RD-JW355 | |
| Ultraviolet-visible spectrophotometric spectroscopy (UV-vis) | Ocean Insight Company of the United States | OCEAN-HDX-UV-VIS |
References
- Chen, W., Cai, S., Ren, Q. Q., Wen, W., Zhao, Y. D. Recent advances in electrochemical sensing for hydrogen peroxide: A review. Analyst. 137 (1), 49-58 (2012).
- Zeng, Z. Y., et al. A bioinspired flexible sensor for electrochemical probin....
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